whats max level for capping ninjutsu in sea?

[Shoko]

He ask how to cap ninjutsu, not throwing.

And the best way to do it is to just cast the elemental ni wheel on hard mobs, they cant be completely resisted so you have a chance at a skill up on every cast. Some of the sea NMs might be able to bring you up to cap, but you should do this in abyssea, you can get regen and evasion atmas, and it would be much easier on you then doing it outside.

You also need to find mobs that con even match to cap your skills, mobs under even match will not cap you out.(unless they changed this at some point and I am not aware of it)

Mobs at Decent Challenge can cap you out now. High level on-the-fence EP mobs can get you pretty high up there as well.